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Homework Help: Finding the impedance of a circuit

  1. Apr 22, 2008 #1
    1. The problem statement, all variables and given/known data
    http://img297.imageshack.us/img297/2951/picqk5.th.jpg [Broken]

    I'm just trying to do part a for the moment.

    2. Relevant equations

    3. The attempt at a solution

    My initial attempt was just trying to find the impedance of the 5 mH inductor and saying that would be Zin. Unfortunately that doesn't seem to be the case.

    Then I tried doing a thevenin type problem where I find the impedance of all the elements to the right of the inductor, but that doesn't seem to work either.

    I also just tried finding Zeq for the whole thing but that doesn't work either, hmm.
    How does one find the impedance between two nodes? I would have thought that the 2nd method would have worked for sure.
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Apr 22, 2008 #2
    Thevenin Theorem should work here. Find the equivalent impedance seen from the nodes a and g.

    (Hint : Fold from the right side to the left side)
  4. Apr 22, 2008 #3


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    No need to use Thevenin, since there is no power source.
    Between nodes b and g there are two elements. Find the impedance of the parallel combination. Between nodes a and b there is a capacitor, that is in series with the impedance bg. Finally, calculate the impedance of the three branches in parallel between nodes a and g.
    A similar reasoning can be made for items b and c.
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